The Fixation of Free Nitrogen¹

Abstract

IN a paper communicated to the Royal Society in 1887-88 1 (Phil. Trans., 1889), the authors discussed the history and present position of the question of the sources of the nitrogen of vegetation. The earlier results obtained at Rothamsted, as well as those of Boussingault, under conditions in which the action both of electricity and of microbes was excluded, led the authors to conclude that the higher chlorophyllous plants have not the power of taking up elementary nitrogen by means of their leaves, or otherwise. The conclusions arrived at were, that atmospheric nitrogen is not a source of nitrogen in the case of gramineous, cruciferous, chenopodiaceous, or solaneous crops, but with regard to the Leguminosœ it was admitted that there was not sufficient evidence to account for the whole of the nitrogen taken up. Of the recent researches bearing on the subject, those of Hellriegel and Wilfarth, first published in 1886, were considered the most striking and conclusive.